In vitro fermentation of beet fibre and barley bran, of their insoluble residues after digestion and of ileal effluents

Abstract

Abstract: The main objective of this study was to determine the form in whichbeet and barley bran Ðbres reach the colon, and to evaluate the inNuence ofendogeneous compounds on their patterns of fermentation. Raw Ðbres (RF), cor-responding ileal effluents (IE) from pigs, and insoluble Ðbre residues (IR)extracted from IE, were fermented with human faecal inoculum for 24 h in an invitro batch system. For beet Ðbre, rate but not extent of cell wall sugars degrada-tion was increased (]34% at 6 h, P\0E05) after oroileal transit, due to a moreporous structure. For barley bran, oroileal conditions degraded endosperm com-pounds such as b-glucans, leading to a lower extent of cell wall glucose fermenta-tion compared with RF ([22% at 24 h, P\0E05). In the presence ofendogeneous substances, degradation of beet Ðbre polysaccharides was delayed(P\0E05) at each incubation time but that of barley bran Ðbre was unaltered.Compared to RF, IR and IE signiÐcantly exhibited lower acetate production forbeet Ðbre, and higher propionate and lower butyrate production for barley branafter 24 h. It is concluded that in vivo digestion modiÐed fermentation patterns ofboth Ðbres in a manner depending on botanical structure.J Sci Food Agric 75, 315E325 (1997)No. of Figures: 2. No. of Tables: 4. No. of